IE902524A1 - A heat and sound insulating product, its use and a method of manufacturing such a product - Google Patents

Abstract

A thermally and acoustically insulating product is described which is used in the construction of ventilated facades. This product consists of a mineral-fibre felt (1) whose outer surface (2) comprises a porous coating based on a polymerised substance (3) which is UV-stable, impervious to surface water and permeable to gases and to vapours. <IMAGE>

Description

A HEAT AND SOUND INSULATING PRODUCT, ITS USE AND A METHOD OF MANUFACTURING SUCH A PRODUCT The object of the invention is a mineral wool based felt, particularly a glass wool based felt intended for heat and sound insulation of walls from the outside, behind attached curtain walls.

The exterior insulation of walls is currently achieved by means of panels or rolls which are stuck or mechanically fixed to the brick wall or concrete wall or which may even be tied or spiked onto the framework of a curtain wall, the panels or rolls then being masked by an attached facing which is preferably situated at a certain distance form the insulant in order to ensure satisfactory ventilation which avoids the risks of condensation of the steam and the damage which such condensation might produce.

This method is very advantageous particularly by virtue of the variety of types of possible curtain walls (fibre-cement panels, slates, tiles, facing bricks, timber facings, metal or PVC cover joints, etc.) and the possibility of working on new or old buildings.

For such use, the mineral wool based insulating products are particularly advantageous by virtue of their likeness, their high mechanical strength and above all the quality of the heat and sound insulation which they provide due in particular to their elasticity and their porosity. These products are typically produced from mineral fibres which are maintained in cohesion by an organic binder (a phenol-formaldehyde resin of the resol type, modified or not with urea, for example). The binder is sprayed in the form of an aqueous sizing when the fibres are received and a layer of sized fibres is - 2 then conveyed into an oven in which the binder is polymerised, and the felt which is thus produced has for this range of applications a density comprised, for example, between 10 and 40 kg/cu.m, the resultant product being produced in the form of panels or rolls.

Exterior insulation is, of course, faced with the problem of bad weather during application on building sites, the final facing providing external protection although generally it can only be fitted after the insulation is completed. To obviate this problem ,it is known to line the felt with a sheet of glass which improves mechanical strength and which protects the insulant from bad weather. However, this protection is only momentary (lasting at most a few weeks) and it is therefore satisfactory only if the work on the site is carried out at a normal rate.

But in practice, numerous work sites are left as they are for very long periods, frequently 3 to 6 months, for reasons of a technical nature or sometimes simply by reason of a breakdown in supplies of surfacing materials. The felt which has thus been placed on the facings is therefore exposed to the free air for a very long period and its outer surface is exposed to various attacks such as solar radiation, ultra-violet rays in particular, rain, wind, dust, heat, shocks of all types. There is then a rapid and progressive deterioration of the superficial structure of the felt: discoloration or at least a change in colour, a tearing of the surface which is exposed to the air, and some strips of fibres may even be torn away.

Over and above the unpleasant appearance which the whole of the building acquires, and which is often unacceptable in itself, this deterioration in the surface - 3 structure likewise produces a considerable deterioration of the organic binder which is weakened by the ultraviolet rays and which is literally washed away from the surface by the rain water running over it. Finally, when work is resumed after the few months of interruption, the felt simply appears to be superficially damaged but if the outer protection is taken away after a few years it will be found that the fibres, or at least some of them, will have dropped for want of binder and will have accumulated in the bottom part of the building.

It has been suggested to paint insulating panels with a latex-based refractory paint which is sprayed onto the outer surface of the panels. However, this technique is not satisfactory with the lightest of products which act like sponges and which therefore require very substantial quantities of paint if a satisfactory resistance to steam is desired. Finnish Patent No. 70 286 proposes obviating this last-mentioned problem by using a glass fibre membrane interposed between the insulating layer and the coat of paint, this membrane reducing the possibility of the latex paint impregnating the insulating layer.

In practice, the authors of the present invention have found that latex paints have a resistance to ultraviolet radiation which is inferior to that which is desired if the insulating product is to suffer prolonged exposure. Moreover the membrane, above all if it is reinforced and thickened by a coat of paint, produces a ’’mat'* effect when the panel is fixed by being pinned on mechanical mountings comprising a stop means in the form of packing rings or roses. This matting phenomenon slightly impairs the quality of the insulation and has, furthermore, the disadvantage of being deemed unattractive by the majority of architects. - 4 The object of the invention is to provide a mineral wool based insulating product consolidated by an organic resin and intended for the exterior insulation of buildings and which is capable of withstanding prolonged exposure to bad weather.

In accordance with claim 1, this object is achieved by a heat and sound insulating product consisting of a felt produced from mineral fibres consolidated by an organic binder which has directly on its outer surface a porous vinyl coating which is stable vis-a-vis ultraviolet rays, and which is proof against running water.

Preferably, the coating consists of a paint of the polyvinyl acetate type, deposited on the surface at the rate of 50 to 70 per sq.m after drying. The paint, preferably fireproofed, may be coloured, for example to the same shade as the organic binder. The very small thickness of the coat of paint is surprisingly adequate to provide the required protection against bad weather and does not change the appearance of the panel once it has been fitted.

The product according to the invention may advantageously be obtained by spraying onto the surface of a strip of felt consisting of mineral fibres bonded by a polymerised resin an aqueous or organic dispersion which will form the porous vinyl coating followed by polymerisation via simple drying at ambient temperature.

Further details and advantageous characteristics of the invention are given hereinafter with reference to the accompanying drawings, in which: Fig. 1 is a sectional view through a product according to the invention, and Fig. 2 is a diagram showing the product in use.

A particular object of the present invention is a heat and sound insulating material consisting of a mineral fibre felt 1 intended for the external insulation of facades, comprising on its surface which is exposed to the weather a porous polymer based coating which is stable vis-a-vis ultra-violet rays, is proof against running water and is permeable to gases and vapours.

The said coating 3 is indeed applied to the felt in such a quantity that it remains porous, so respecting the actual structure of the mineral fibre felt. This porosity is necessary because, for it to play its part to the full, the insulating material must be able to allow air and vapours through its mass, particularly when it is not protected by an external cladding. By remaining in the dry state, its heat insulating capacity is enhanced.

To be able effectively to fulfil its function of providing mechanical protection (resistance to wind pressure or rain, resistance to the tearing away of fibres), the coating 3 must have a sufficient solid structure, a structure which is achieved by the use of adequate polymerised substances. The polymerised substances which may be used according to the invention are vinyl polymers or copolymers of the polyvinyl acetate or polyvinyl chloride type. Furthermore, in order to make sure that the material has long lasting properties, the coating 3 must be stable in respect of ultra-violet rays which, in the long term and in large quantities, can cause 'cracking' of the polymer chains, a phenomenon from which it is desirable to preserve the resin used for gluing the fibres and which in course of time becomes superficially depolymerised, producing an irremediable tearing away of strips of fibres.

The resistance of the coating 3 to the action of ultra-violet rays is achieved by using suitable prior art - 6 additives. The nature of the polymerised substances may likewise play an important role in this phenomenon.

In place, the strips or panels of felt 1 are disposed vertically. In such a situation, the coating 3 ensures tightness in respect of running water, rain or flows of all kinds. When the rail is driven by the wind, sealing-tightness can no longer be guaranteed with the same efficiency but the porous nature of the said coating then fulfils its role by allowing the water vapours present within the mass when it stops raining to pass through it.

By the term ‘mineral fibres', within the meaning of the present invention, it is intended to refer to glass wool or rock wool, for example.

In view of its intended use (insulation of building facades), the material according to the invention is preferably fireproofed: fireproofing is achieved by using suitable substances which are normally distributed within the coating 3, for example aluminium hydroxide. The quantities of fireproofing agents will be determined as a function of the standards which have to be met.

The aesthetic aspect of the problem must not, as stated earlier, by neglected and the coating 3 may advantageously be coloured by using organic and/or mineral pigments which are stable when exposed to ultra-violet rays. Such pigments are well-known to a man skilled in the art and are currently available commercially.

With regard to quantities of coating 3 applied to the outer surface 2 of the felt 1, good results are obtained with quantities comprised between 50 and 70 g/sq.m, it being understood that such amounts may be disregarded according to the aims which are being sought. Too thin a layer would, however, adversely affect the - 7 desired mechanical strength, whereas too high a content, for example one which is markedly greater than 70 g/sq.m, would compromise the quality of the whole, as the desired porosity would not be achieved.

Another object of the invention is a method of producing the insulating material described above. This method is characterised in that, in a predetermined quantity, the outer surface 2 of a mineral fibre felt 1 is coated with an aqueous or organic dispersion intended to produce a polymerised substance which is stable vis-avis ultra-violet rays, the coated surface then being dried.

This coating is carried out at the factory, at the end of the mineral fibre felt production line, using any suitable apparatus, an inking roller or a spray gun, for example. The dispersion used comprises mixtures adapted to generate the desired polymers or copolymers, the stabilising anti-ultra-violet agent and, if applicable, the pigment or pigments selected. The dispersion may be aqueous, organic or even organic-aqueous; it is applied to the surface 2 of the felt in such quantities that after drying, a coating results which has a suitable weight per unit of surface area, preferably 50 to 70 g/sq.m. The actual polymerisation is carried out more generally by drying at a temperature of around 150°C, by means of a current of hot air or by means of infra-red radiation.

Once the felt 1 has been finished and dried in this way, it is cut into strips or panels of the desired dimensions. These felt strips or panels are then ready for use.

They are preferably used as follows: the felt 1 is disposed on a concreted facade 4, for example, the surface containing the coating 3 being of course exposed - 8 to the free air. The felt strips or panels are fixed to the facade 4 by gluing, for example, or by means of rods, pellets or studs, for example. To produce the ventilated facades proper, supporting rods 6 are pushed into the mass of concrete 4; spacing elements 7 are disposed on the rods 6 which support the panels 5 in order to guarantee that the space is uniform.

The following example is given purely by way of information: * glass wool felt, density around 30 to 36 kg/cu.m, phenol formaldehyde resin (8%), * organic dispersion containing approx. 60% polyvinyl acetate, polyvinyl chloride and polyethylene, stable to ultra-violet rays and fireproofed by the addition of Al(OH)^ - density 1.40 to 1.42 - viscosity 720 mPas., * coating by spray gun followed by drying at 150°C for approx. 15 minutes. When this dispersion is also coloured by means of pigments, no change in colour is noted after drying, * end product: a panel or strip of felt approx. 30 mm thick - covering: 60 g/sq.m.

Tests in a real situation (rain, wind, sun) have shown that such an insulating material suffered no notable deterioration on the surface after six months' exposure. As a rule, such a period is amply sufficient for fitting the outer cladding which constitutes the ventilated facade.

Claims (14)

1. A heat and sound insulating product consisting of a felt (1) of mineral fibres consolidated by an organic binder, intended for the exterior insulation of facades, characterised in that it comprises on its outer surface (2) a porous vinyl coating which is stable vis-avis ultra-violet rays, which is proof against running water and which is permeable to gases and vapours.

2. A product according to claim 1, characterised in that the coating (3) is a polymer of the polyvinyl acetate or polyvinyl chloride type.

3. A product according to one of claims 1 and 2, characterised in that the coating (3) is fireproofed.

4. A product according to one of claims 1 to 3, characterised in that the coating (3) is coloured by means of organic and/or mineral pigments.

5. A product according to one of claims 1 to 4, characterised in that the coating (3) is deposited on the outer surface (2) of the felt (2) at the rate of 50 to 70 g/sq.m after drying.

6. A method of producing an insulating product according to one of the preceding claims, characterised in that, in a predetermined quantity, the outer surface (2) of a mineral fibre felt (1) is coated with an aqueous or organic dispersion to produce a polymerised substance stable vis-a-vis ultra-violet rays and in that the surface thus coated is then dried.

7. A method according to claim 6, characterised in that coating is carried out in such a quantity that after drying the dispersion, a coating (3) remains which is distributed at the rate of 50 to 70 g/sq.m. Ί - 10

8. A method according to one of claims 6 and 7, characterised in that the dispersion contains fireproofing substances and, if necessary, organic and/or mineral pigments.

9. Use of a heat and sound insulating material according to one of claims 1 to 5 for the construction of ventilated facades.

10. A heat and sound insulating product substantially as herein described with reference to and as shown in the accompanying drawings.

11. A method of producing an insulating product substantially as herein described with reference to the accompanying drawings.

12. An insulating product whenever produced by a method as claimed in any one of Claims 6 to 8 and 11.

13. Use of a heat and sound insulating material for the construction of ventilated facades substantially as herein described with reference to and as shown in Figure 2 of the accompanying drawings.

14. The features described in the foregoing specification, or any obvious equivalent thereof, in any novel selection.